Circuit breaker



DCC. 14, w M. LEEDS CIRCUIT BREAKER Original Filed May 20, 1930 WITNESSES:

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R/ BY ATToR EY Patented Dec. 14, 1937 l' UNITED STATES PATENT OFFICE CIRCUIT BREAKER Winthrop M. Leeds, Wilkinsburg, Pa., assigner .to Westinghouse Electric & Manufacturing Company, a corporation of Pennsylvania.

44 Claims.

My invention relates to circuit-intermpters and particularly to arc-extinguishing devices therefor. This application is a division of my copending application Serial No. 453,909 led May In Patent No. 1,899,605 of B. P. Baker, et al., issued February 2B, 1933 and assigned to the assignee oi this application, an arc-extinguishingdevice is disclosed comprising a plurality of l insulating and magnetic plates arranged in stacks to constitute arc-extinguishing structures and containing aligned slots adjacent to anv arc path that is established between separated contact members. The arc, so established, is moved into the slots where it is deionized and extinguished because of the distortion of the surrounding ileld in the presence of magnetic plates.

supplementing this structure, the present application has for its object a more effective ar- 2@ rangement and location of the slotsin the plates to provide deeper slots and a. greater distance over which the arc may travel in order that the speed of arc movement may be increased.

A further object of my invention is toA provide a radial magnetic field associated with the lower part of an arc-extinguishing device of the above described type that shall produce an increasedV magnetomotive force for moving the arc when the current thereof is below a predeterm .ned value.)

For a more complete understanding of the nature and objects of my invention, reference may be had to the following description, taken in conjunction with the accompanying drawing wherein:

Figure l. is a sectional View, in elevation, of a circuit interrupter embodying my invention.

Fig. 2 isa plan view on an enlarged scale of 40 a modified arc-extinguishing device embodying my invention, having a conducting plate provided on the top thereof upon which the arc terminal may be moved and having pockets for retaining oil. y i

4 Fig. 3 is a sectional plan view cf an :arc-

extinguishing device embodying my invention, taken on the line III- III of Fig. .4, and

Fig. 4 is a vertical sectional view of the device shown .in Fig. 3, taken along the line IV-IV 50 thereof. Y

My invention comprises, in general, a casing I having a cover 2 thereon that supports conductor bushings 3 and 4 in a manner that is well known in the art. The bushings 3'and'l 55 support the terminal members 5 and 6, respec tively, which are conductively joined by a movable bridging member 1.

A lift rod 8 supports the bridging member 'I and extends through the cover 2 where it is actuated by a mechanism (not shown) to op- Il erate the bridging member to open and to closed position. Arc-extinguishing structures 9 are supported on the terminal members and 6, respectively and are immersed in a quenching liquid il contained within the casing i. 10

The arc-extinguishing device 9 comprises a plurality of insulating plates I6 having curved slots I5 and built up into a stack having a plu-I rality ci magnetic plates Il distributed throughout its .length and insulated by insulating liners I8. A vent I3 is provided from the slot i5.

When the arc is drawn, by movement of the bridging member l, away from the terminals 5 and E, the magnetomotive force set up in the magnetic plates I1 so distorts the magnetic field 20 about the arc that the arc is normally moved toward the closed end of the slot i5. The gases generated by the decomposition of the quenching uid II in the slot I5, as a' result of the intense heat of the arc, are disposed within the slot between the arc and the inner end thereof and are forced through the arc as it is moved toward the rear of the slot to deionize it, the gases `then escaping through the vent I3.

The curved path of the slots I5 provides an 30 increased slot depth without increasing the outside dimensions of the arc-extinguishing device, in order to make possible the movement of the arc byvmagnetic means at higher velocities. In the modiilcation shown in Fig. 2, pockets I9 in alternate plates I6 are formed by providing narrowedportions along the periphery of the curve I5 so that the fluid is trapped and retained so as to be available for feeding .into the arc as the are is moved through the slot. Other plates 40 I 6 are formed with a narrow curved slot I5 which converges in width in the direction of arc movement. These plates provide inwardly projecting longitudinally spaced ribs along the arc passage which serve to restrict the are in sections as it is moved along the passage.

A metal plate 20 is provided on the top of the arc-extinguishing device 9, as shown in Figs. 1 and 2. The stationary terminal members 5 and 50 6 are directly adjacent 4and electrically connected to the plates 20 upon which the arc terminals are transferred and moved during the downward movement of the bridging member 1. By moving the are terminal across the plate, the upperplates 55 of the stack are utilized more emciently, the arc is lengthened inthe general shape of a helix, the upper contact has a longer life, since the burning is distributed over a greater. area, and restriking of the arc is more dicult, since the upper hot arc terminal is moved-away from the position directly above thelower arc terminal on the bridging member.

The arc is moved into the slot i5 'under the action of the magnetic eld due to the `arc current. This iield around the arc stream is distorted due to the open-ended slot in the iron plates `ll and thus exerts a force on the arc to move it into the slot. v'ihe strength of the magnetic field which moves the arc into the slot therefore depends on the magnitude of the arc current, and when small currents are interrupted, there will be a relatively small force to move the arc into the slot. This motion of the arc is opposed by the outward flow of the gas `formed by the decomposition of the arc extinguishing uid trapped in the slot. In some cases with small currents the magnetic field set up by the single turn formed by the arc may not be sucient to overcome the force exerted by the gas so that the arc is not moved into the slot Where the current to be interrupted is large, there is a strong magnetic field to rapidly move the arc into 'the slot. This causes the generation of a large amount of deionizing gas which is moved through the arc, resulting in its extinction before the moving contact has moved the whole length of the' stack of plates. To interrupt smaller currents it may be necessary to draw the arc the whole length of the stack before it is extinguished.

As pointed out above, when the current is less than a predetermined amount, the gas pressure, built up ahead of the arc, may overcome the-magnetic driving force produced by the presence of the iron plates il and tend to force the arc back out of the slotl.

To prevent such movement, provide a plurality of pairs of windings 2l and 22 that are adapted to be connected in series with the arc, if it becomes a predetermined length, as shown in Figs. 3 and 4. When the arc current is above the predetermined value, the arc will beextinguished The windings 2i and '22 are .diierentially as;

sociated with veach other to produce magnetic elds in the saine direction across the upper and lower air gaps 2li of the iron circuit 25 of each section as indicated by arrows 3l and 32. The iron path 25 is provided as ay common return for the flux from both air gaps. Conducting plates 23 are connected to each oi the windings 2l and 22 and are so placed that the terminals or" the sectionalized arc are moved thereon. insulation 2@ is provided between the windings 2i and 22 and the ironcircuit 25 and also between adjacent sets of windings of the structure. The slotted section and the insulating plates are held together to form a unitstructure by a through bolt 2l.

In this construction, when an arc is established by the bridging member i, the plates il so distort the magnetic neld about the arc that aioaeae the arc is moved along in the slot l5 where, if the arc current is suiciently large, the arc will be extinguished before it is drawn the iull length of the slot.

On the other hand, ii the arc current is insu'icient, in the presence of the plates il, to produce this movement, the arc extinction will be delayed and the arc will be drawn nearly the iull length of the slot. The arc will then be sectlonalized by the plates 23 and' the coils 2l and t2 inserted in series therewith. vThe coils set up a radial eld acrossthe slot l5 as indicated by arrows 33 in Fig. 3 that causes the sectionalized arc to rapidlyv move therein, and become quickly extinguished in the manner characteristic of this type o1" device.

It will thus be seen that I have provided an ar -extinguishing device with means for causing the gases generated therein to promote efficient arc extinction. Conducting plates are provided for transferring the arc terminals thereon in order that the terminals may be moved *o pro@ vide cold cathodes for the arc. en the arc current is below a predetermined value, windings are inserted in series therewith that producean increased magnetomotive force for moving the arc through the oil that is trapped along the periphery of the slot.

While I have described several embodiments of my invention, it is to be understood by those skilled in the art that many changes, additions,

omissions and substitutions may be made therein without departing from the spirit and scope of my invention'as set forth in the accompanying claims.

I claim as my invention:

l. The combination with a circuit interrupter having separable contact members for drawing an arc, and a plurality of insulating plates having alined slots adjacent to the arc path, of magnetic plates associated with a portion of said insulating plates for moving the arc in the space formed by said slots, and a coil associated with the remaining portion of said plates for increasing the' force to move the arc when the arc is moved into` the slots oi' the last said portion of the plates.

2. The combination with a circuit interrupter having separable contact members for drawing an arc, and a plurality of insulating plates having alined slots that are adjacent to the arc path, of magnetic plates associated with a portion oi said insulating plates for moving the arc in the space formed by said slots, radial eld coils associated with the remaining portion of said plates and means for inserting said coils in series with the arc as the arc is moved in the slots.

3. The combination with a means for establishing an arc, and a plurality of insulating plates having alined curved slots associated with the arc path, means for moving the arc in the slot when the current thereof is above a predetermined value, and a coil for obtaining arc movement only when the current thereof is below said value.

4. In a circuit interruptor, means for causing an arc, a plurality of conducting members between which the arc plays, some of said conduct-- ing members splitting the arc up into a plurality of short'sections and one pair of said conducting members having a wide space therebetween leaving a considerable portion of the arc in one section having a length several times the length of each of said short sections, a coil for setting up a magnetic eld to rotate the arc among said conducting members, and means which supplies 7.5

Ved to break up the arc incident to the opening of a circuit and to simultaneously whirl the arc portions through circular paths between the plates, substantially as described.

6. In an arcextinguisher, means of insulating material having walls for defining a generally annularly shaped narrow slot therebetween,l said slot having a relatively long portion permitting a relatively long arc to play therein in one section, a coil having its turns generally concentric with said annularly shaped slotfor causing a radial magnetic field across said slot for rotating at least one portion of the arc in the slot, means for initially establishing'the arc in said slot and said slot having a material therealong which when acted .upon by the arc gives off gas to aid in extinguishing the arc.

'7. In an arc extinguisher, means of insulating material having walls for defining a'generally annuiarly shaped narrow -slot therebetween, said narrow slot having a length at least several times its width in which an arc of considerable length may' play in one section, a coil having its turns generally concentric with said annularly shaped slot for causing a radial magnetic field across said narrow slot for moving the arc laterally along said walls, and means along said slot which when acted upon by the arc gives ofi gas to aid in extinguishing the arc.

8. In an arc extinguisher, means of insulating lmaterial having walls for defining a'generally annularly shaped narrow slot therebetween, said narrow slot having a portion of a length several times its width in which an arc of considerable length may play in one section, a coll having its turns generally concentric with said annularly shaped slot for causing a radial magnetic field across said narrow slot for moving the arc laterally along said walls, and means along said slot which when acted upon by the arc gives off gas, means for venting said narrow slot, and said walls for defining the narrow slot directing a. blast of fluid toward said venting means and holding the arc in the path of said blast of fluid.

9. In a circuit interrupter, means of insulating material having walls'defining a substantially annularly shaped passage therebetween, a

, contact member having a portion movable in 'the passage, longitudinally thereof to establish the arc, a coil having its central axis extending longitudinally of the annularly shaped passage adjacent the center thereof for setting up a mag? netic field across the path of said contact member and across saidannularly shaped passage for moving the arc therein, and 'said annularly shaped passage including means which gives oif gas when acted upon by the arc to aid inentinguishing Vthe arc. f Y

1 0. In an arc extinguisher, means of insulating y material having a passage therethrough of a generally annular shape, an arc terminal `member having an arc path thereon oi generally annular shape, means for initially establishing the arc in said passage inv which it may play with one end on said arc terminal member, a coil having its turns generally concentric with said arc terterminal member having an arc path thereon of generally annular shape, said slot having a length at least several times its width to permit an arc to play therein in at least one long section with o 'ne end of said long section on said are terminal member, a coil for connection in the circuit to set up a magnetic field across said slot for'causing the are to rotate in the slot with one end rotating on said arc terminal member, and the major part of the slot along its depth being so narrow as to prevent substantially any movement of the arc in a direction lateral to the path of rotation.

12. In an arc extinguisher, means of insulating material having a pairvof opposed walls deilning a slot havinga generally annular shape, an arc terminal member having an arc path thereon of generally annular shape, said passage having a length at least several times its width to permit an are to play therein in at least one long section with' one end of said long section on said 'arc terminal member, a coil having its turns generally concentric with said arc terminal member electrically connected in the circuit to set up a radial magnetic field across said slot for causing the arc to rotate in the slot with one end rotating on said arc terminal member, means along said slot which gives off gas when acted upon by the arc, vents from the slot for said gas, and said slot directing a blast of fluid toward said vents and holding the arc from moving laterally of the direction of rotation of the arc out of the path of said blast of uid.

13. In an arc extinguisher, means of insulating material having a pair of opposed walls defining a slot having a generally annular shape, a pair of arc terminal members each providing a path for one termini of the arc thereon of generally annular shape, said pair of arc terminal members ,after the arc is established being spaced apart a distance at least several times the width of the slot to permit a, long' arc to play therebetween, and said slot of generally annularA shape being so narrow over the major part of its depth as to confine the movement of the arc to a predetermined line, means for causing rotation of the whole length of the arc between said pair of arc terminal members along said line, and means along said slot which gives E gas when actedupon by the arc to aid in extinguishing the arc.-

Y 14. In/a circuit interrupter, means of insulating material having walls defining a substantially annularly shaped passage therebetween, a con--- tact member having a portion movable in the passage axially thereof to establish the arc, a pair of arc terminal members spaced apart along said means cf insulating material a distance at least several times the -width of the passage for' receiving the arc and permitting it to play in at least one long section, each of said arc terminal arranged and adapted to 'break up the arc incident to the opening of a circuit and to simultaneously whirl the arc-portions through circular paths between the plates, substantially as described.

26. In an arc extinguisher, a plurality of spaced plates of conducting material each providing an annularly shaped path for the arc, a coil which when energized sets up a 'radial magnetic field across said annularly shaped arc paths, an opening through a plurality of said plates-of conducting material, said opening having a portion withsaid members of conducting material, means forcausing an arc to play in said opening, and said opening having a portion within the magnetic eld for rotating the arc.

28. In an electric switch or circuit breaker, the combination of a xed and a movable contact piece, a structure including means of insulating .material having an aperture through which the movable contact can pass, a magnet pole passing through the structure and situated at one side of the said aperture through the structure, and a magnet winding situated at. one end of the said magnetic pole, the whole being arranged and adapted to whirl the arc through a circular path in the structure. l

29. In a circuit interrupter, the combination ofmeans for establishing an arc, a structure of insulating material having an aperture forsaid means for establishing the arc, said aperture having a generally circular portion in which the arc may be rotated, a magnet winding having its central axis passing through the structure at one side of the said aperture and adjacent the center of lsaid circular portion of the aperture, said magnet winding when energized Asetting up a radial magnetic field across said means for establishing the arc and across said circular portion of the aperture for rotating the arc therein.

30. In a circuit interrupter, the combination of means for establishing an arc, Aan arc extinguishing structure having an aperture in which the arc is established by said means, said aperture having walls of insulating material and having an annularly shaped portion in which the arc may be rotated, a magnet winding having it central axis passing through the structure and situated at one side of and generally parallel to the path through said aperture along which the arc is established, said magnet winding when energized setting up a radial magnetic field across said portion of the aperture where the arc is established and across said annularly shaped portion of the aperture for moving the arc therein.

31. In a circuit interrupter, the combination of means for establishing an arc, an arc extinguishing structure having an aperture in which the arc is established by said means, said aperture having walls oi insulating material and having an annularly shaped portion in which the arc may be rotated, said annularly shaped portion of the aperture closely conning the arc and havin'g'a material therealong which when acted upon by the arc gives off gas to aid its extinction, a magnet winding having its central axis passing through the structure and situated at one side of and generally parallel to the path through said aperture along which the arc is established, said magnet windingwhen energized setting up a radial magnetic eld across said portion of the aperture where the arc is established and across said annularly shaped portion of the aperture for moving the arc therein along said gas forming material.

32. In a circuit interrupter, the combination of means for establishing an arc, an arc extinguishing structure having an aperture in Awhich the arc is established by said means, said aperture having-walls of insulating material and having an annularly shaped portion in which the arc may be rotated, a pole piece of magnetic material passing through the structure adjacent the center of said annularly shaped portion of the aperture generally parallel to the path along which the arc is established, a magnet winding around said pole piece, said winding when energized causing a radial magnetic eldacross said portion of the aperture where the arc is established and across said annularly shaped portion of the aperture for moving the arc therein.

33. In a circuit interrupter, the combination of means for establishing an arc, an arc extinguishing structure having an aperturein winch the arc is established by said means, said aperture having Walls of insulating material and hav-j ing Van annularly shaped portion in which the arc may be rotated, said annularly shaped portion of the aperture closely confining the arc and having a material therealong which when acted upon by the arc gives off gas to aid its extinction, a pole piece of magnetic material passing through the structure adjacent the center of said annularly shaped portion of the aperture generally parallel to the path along which the arc is established, a magnet winding around said pole piece, said winding when energized causing a radial magnetic iield across said portion of the aperture` where the arc is established and across said annularly shaped portion of the aperture for moving the arc therein. Y

34. In a circuit interrupter, the combination of means for establishing an arc, an arc extinguishing structure having an aperture in which the arc is established by s -aid means, said aperture having walls of insulating material and having an annularly shaped portion in which the arc may be rotated, an arc terminal member at at least one end of the aperture and having an annuiarly shaped portion on which one end of the arc is rotatable, a magnet winding having its central axis passing through thestructure and situated at one side of and generally parallel to the path'through said aperture along which the arc is established, said magnet winding when en- 'ergized setting up a radial magnetic field across said portion of the aperture where the arc is established and across said annularly shaped portion of )the aperture for moving the arc therein.

35. In a circuit interrupter, the combination of means for establishing an arc, an arc extin-vl guishing structure having an aperture in which the arc is established by said means, said aperture having walls of insulating material and having 'an annularly shaped portion in which the arc may be rotated, said annularly shaped portion of the aperture having a length at least several times its width to permit the arc to play therein in at least one long section, a magnet winding having its central ams passing through the structure and situated at one side of and generally parallel to the path through said aperture along which the are is established, said magnet winding when energized setting up a radial magnetic eld across said portion of the aperture where the arc is established and across said annularly shaped porn tion of the aperture for moving the arc therein.

k36. In a circuit interrupter, the combination ofineans for `estaloli'slriing an arc, an are en tinguishing structure having an aperture in which the arc is established by said means, said aperture having walls ci insulating material and having an annularly shaped portion in which the are may be rotated, said annularly shaped portion oi the aperture having a length at least several times its width to permit the arc to play Vtherein in at least one long section, an arc terminal member at at least one end of the aperture and having an annularly shaped portion on which one end or the arc is rotatable, a niag-1 net winding having its central axis passing through the structure and situated at one side of and generally parallel to the path through said aperture along which the arc is established, said magnet winding when energized setting up a radial magnetic field across said portion oi' the aperture where the arc is established and across said annularly shaped portion of the aperture for moving the arc therein. l Y

37. In a circuit interrupter, the combination of means for establishing an arc, an arc ex tinguishing structure having an aperture in which the are is established by said means, said aperture having walls of insulating material and having an annularly shaped portion in which the arc may be'rotated, saidannularly shaped portion of the aperture closely conning the arc and having a material therealong which when acted upon by the are gives oil gas to aid .its extinction, a v ent from'the aperture Iwhich is open during the extinguishing of the arc to permit the escape of the gas, a magnet winding having its 1 central axis passing through the structure and situated lat one side of and generally parallelto the path through-said aperture along which the arc is established, said magnet winding when energized setting up a radial magnetic ield across said portion of the aperture where the arc, is established and across said annularly shaped portion of the aperture for moving the arc there--l in along said gas forming material. v l

38.' In a circuit interrupter, the combination of means for establishing an arc, an arc extinguishing structure having an aperture in which the are is established bysaid means, said aper ture having walls of insulating material and have ing an annularly shaped portion in which the are may be rotated, said annularly shaped portion ofthe aperture having a length at least several times its width to permit the are to play therein in at least one long section, an arc ter-I minal member at at least one end of the aper=- ture and having an annularly shaped portion on which one end ol the arc is rotatable, said aus nularly4 shaped portion of the aperture closely conning the arc and having amaterial therealong which when acted upon by the arc gives ed gas to aid its extinction, a vent from the aper ture which is open during'theextinguishing ci thev arc to permit the escape of the gas, a magnet winding having its central4 axis passing l through the structure and situated at one side of and generally parallel to the path through said aperture along which the arc is established,

said magnet winding when energized setting up a radial magnetic eld across said portion of the aperture where the arc is established andA across said annularly shaped' portion of the aperture passage, and means for moving the arc laterally along said passage, the said walls ci said pas= sage being gradually convergent in the direction of arc movement from the entrance of said passage for gradually restricting the cross-section of the arc, said side walls also having opposed in11 Wardly projecting longitudinally spaced ribs for restricting portions ci the arc without materially increasing the resistance to movement of the arc along said passage.

so. In an arc extinguisher for circuit breakers, means of insulating material deug the walls of a slot-like substantially enclosed arc passage, means for drawing an arc longitudin of the passage, and means for moving the arc laterally along said passage, the said walls or said passage being gradually convergent in the direction of arc movement from the entrance of said passage for gradually restricting the cross-section of the arc, said side walls also having opposed inwardly projecting longitudinally spaced ribs for restricting portions of the arc without materially increasing the resistance to movement of the arc along said passage, and a material within said passage which gives oil a gas when acted upon by an arc to aid in extinguishing the arc, the side walls of said, passage having pockets positioned producing material along said passage.

, 41. In an arc extinguisher for circuit break@ ers, means of insulating material defining the walls of a slot-like' substantially enclosed arc passage, means for drawing an arc longitudinally ofthe passage, and means for moving the therein between said ribs for retaining said gas remaining portions ci said side walls to con tract the arc stream into a plurality of restricted sections and to increase the creepage distance lengthwise of said passage.'

425111 an are extinguisher for circuit break= ers, means of insulating material de fi-...r the .walls of a slotnlike substantially enclosed arc passage, said passage being enlarged at the entrance thereoi, a pair oi separable contacts Witlilny said enlarged portion for establishing an arc longitudinally of said passage, means for moving said .arc laterally along said passage, said passage having a tapering portion exten from said enlarged portion in the direction of arc movement for gradually restricting the crosssection of the arc, the walls of said passage hav-s ing ribs spaced longitudinally of thepassage ,and extending from` the enlarged'entrance 'portion toward the rear of the passage for contracting said arc into 'a plurality of restricted sections without materially increasing the resistance to movement of the arc alongsid passage, and a liquid within said passage w ch gives on a gas when acted upon by said arc to ald in extinguishing the arc.

43. In an arc extinguisher, means of insulatn ing material having walls for deiinlng a generally annularly shaped narrow slot therebetween, said narrow slot having a length at least several times its width in which an arc o! considerable length may play in one section, a coil having its tums generally concentric with said annularly shaped slot for causing a radial magnetic field across said narrow slot for moving the arc laterally along said walls, means along said slot which when acted upon by the arc gives of! gas to aid in extinguishing the arc, and venting means for conducting the gas produced by the arc exteriorly o! said narrow slot, said venting means being with respect to said narrow slot and the are path therein to cause a ilow of gas through the arc stream.

44. In an arc extinguisher. means of insulating material having walls for definingl a generally annularly shaped narrow slot therebetween, said narrow slot having a portion o! considerable length in which an arc of considerable length may play in one section, a coil for magnetically moving the arc laterally along said walls, a plurality of recesses along one or more of said walls of the slot, said slot having means therealong.

which when acted upon by the arc gives oi! gas to aid in extinguishing the arc, and vents along said slot for the escape oi' gas therefrom, the walls ot said slot directing a ilow of gas through the are toward said vents.

OP M. LEEDS. 

